Overworked and overheated brakes can lead to several braking issues. How many times have you heard front end shuddering under hard braking that was blamed on warped rotors? Reasonably, excessive heat could affect the metal rotor surface, causing warping and the resultant vibration. Rotors are often machined and resurfaced in an attempt to cure the issue. However, the problem usually recurs after a short time.
Assuming your wheel hub and brake components are in good condition and your wheel bearings are in decent shape, warped brake discs are still generally not the issue causing the vibration. In most cases, the cause is pad friction material that has transferred unevenly to the disc surface. This can result in very slight rotor thickness variation, inconsistent braking action, and the observed vibration.
As the pads come in contact with the rotor under braking pressure, some pad material separates from itself and can transfer to the rotor surface. When pads are pushed past their temperature limit, pad material may transfer to the rotor unevenly, resulting in rotor thickness variation.
It's critical to choose brake pads based on application, but it's just as important to ensure the pads undergo a proper break-in, according to the manufacturer's instructions. Failure to bed-in pads after installation may quickly lead to uneven pad-material transfer and the start of brake vibration issues.